METHOD FOR INJECTION MOLDING A THIN HOUSING FOR A PORTABLE TELEPHONE

摘要

In order to mold with good yield a thin housing for a portable telephone having good properties such as a very high bending strength and a good molded surface without any surface sink, as shown in Fig. 3, after resin is injected from a pin gate (4) in a front mold (1) into a cavity (31), projecting members (28) are caused to project into the cavity (31) while the resin remains in a molten state, and push button insertion holes including the pin gate portion (4) are made by punching in such a manner that the ends of the projecting members and resin are pushed together into fit-in holes (12). Simultaneously, after a pin for forming a tapping hole in a boss forming hole (29) is slightly pushed into the cavity (31), the resin is cooled and set, and thereafter both front and back molds are separated, thereby molding a thin housing for a portable telephone.